When Does It End, Where Does It Begin
by PurpleYin
Summary: The whole world died on a Thursday – relegated to little more than animals – however, some of them take a while longer to realise it than the obvious ones who get back up when they shouldn't. Sherlock and Molly, with Mycroft and peripheral John.


Warnings: for off-screen character deaths, references to violence and sexual themes

Spoilers: None

A/N: Fabulously betaread by sunken_standard. All remaining mistakes are my own.

* * *

If he has one regret it is that he should not have brushed off Mycroft's cryptic warnings. Sherlock has had three years to reflect on the hidden meanings in those text messages and it was so obvious if he'd simply thought about it for fractionally longer. Pettiness made him dismiss it as irrelevant, annoying distractions from Mycroft, and as a result they were not in the right place at the right time.

He'd taken the case he shouldn't have, he'd dragged John into it. Dangerous. Reckless. That was all fine. John accepted that, but had he known... And Sherlock held the pointers to the relevant data in his brain. John had been uninformed because Sherlock had ignored what he was told.

They'd headed right into the thick of it, blindly chasing a mystery that was so much more than the usual, tiresome crimes. Unpredictably so, it seemed. That was what John had thought, no blame placed. He'd been wrong and Sherlock hadn't ever corrected him on that. Mycroft predicted it.

Mycroft was prepared.

Mycroft was sitting pretty, hermetically sealed away with Her Majesty and a couple hundred political bores. Sometimes Sherlock adores that coincidental punishment, because on occasion he has wanted to stand in front of his brother and shout at him, deplore him for asking them to give it a miss, for leaving in enough details it was _interesting _instead of concerning.

* * *

Sherlock lived for the thrill back then, chasing the adrenaline rush as much as the heady, satisfying euphoria of being unequivocally correct. He feels sick on it now. Gut-wrenching nausea every time they make a run. Hammering heart. Effort to breathe evenly.

They rarely get far in one day, holed up in secure locations for days and weeks at a time until danger has passed - and it never does, not entirely, that's why the feeling lingers in the pit of his empty stomach. He's _genuinely_ starving and it does not help the situation, but he can manage.

They survive. Another challenge to rise to. The ultimate competition, us or them, and he can't let them win again.

* * *

At first he carries on because he has to find Mycroft and stare him down - he wants his brother to see the deadness of his eyes now, to see how much worse he is than any of the monstrous things crawling the streets. Sherlock wouldn't kill him, nor would he lay the guilt at his feet; he'd merely show Mycroft the truth as he always does. What Mycroft will do with it, what it will feel like when he sees, is anyone's guess.

This mission of his is the return message never sent.

This number is currently unavailable. Network down.

Do it the old fashioned way.

* * *

A few weeks in and he has another reason to solve the hellish puzzles thrown at him. He's been tracing familiar territory in his search for safe places, getting his estimations right about 70% of time, and this time being wrong he's racing along a street when he stumbles across a house he knows. Climbing the flimsy trellis onto the top of the bay window, a knock on the 1st floor window results in it opening and him nearly becoming yet another tedious member of the horde haranguing him.

"Sherlock?"' exclaimed a considerably weary yet still recognisable person to him – Molly Hooper.

That explained the draw to this location. It wasn't the best hideout building in the neighbourhood but it was known, visited on eleven occasions previous, and quantifiably safer.

"What the...Wait, are you _you_? Say something!"she babbles in a panic, clearly unable to decide if he is a threat given his actions versus the bloody, partially shredded presentation of his suit.

He hung back, half off the ledge, fingers precariously gripping the sill of the window that had all but smacked him in the face.

"Much as I'm flattered you'd think me more capable of complex acrobatics were I one of those fiends, I am currently very much myself and would prefer to stay that way. In short, I'd appreciate a little help extracting myself from near death."

"You could've just said 'yes,' you know," Molly said as she grabbed his lapels and tugged him back onto firm footing.

"Well? Are you going to invite me in?"

After a thoughtful pause she asked, "You're not a vampire, are you?"

"_Molly._"

"What? It's worth checking, considering... recent events."

* * *

He stayed there with Molly until the last of the baked beans and cup-a-soup ran out. By that time they had an escape plan with marginal chances of success. She'd put up surprisingly effective barricades on the lower flats and enough strategically positioned homemade weapons to reassure, but he was keen to impress upon her the dangers of falling into a false sense of security. It was her home, naturally she felt safe there and had gone to every effort, using all resources available to her, to keep it that way.

It wasn't going to last though. He knows from experience.

* * *

She asks where he was when it happened, who he was with. He answers matter-of-factly, but he can tell Molly knows he is deliberately leaving out details. She never pushes for them, she accepts the present and isn't wrapped up in the past. Just as well, he'd find that insufferable and besides which, self-involvement in that manner has proved deadly for several of his temporary travelling companions; people who tagged along, recognising his competence but who could not keep up in the end. He hopes Molly will continue to be different in that regard.

He never asks her where she was. Neither of them bring it up again, even though it is the natural shared bonding moment all survivors he has come across try to force upon him. That memory is left intact and solitary until one night, when they get trapped in the practically empty storeroom of a supermarket.

They're perfectly safe in there, nothing is getting in. Unfortunately, that means they're not getting out either. They sit taking swigs of a concoction of wine mixed with Coca Cola. A 'Freddy Kruger,' she called it, some pop-cultural reference he didn't understand and that made her giggle; he'd pointedly avoided mentioning the price tag of £40 per bottle. They require the sugar content; if there is any other reason to drink, it is to their inevitable deaths though he is not willing to suggest it as an option quite yet.

He wonders, halfway through a large measuring jug's worth of the simple cocktail, if he can make himself numb enough that being eaten alive won't hurt, or that the images of it happening to others in his nightmares won't haunt him so vividly.

He's far too drunk when he asks. Horribly unastute, inhibitions lowered so much he doesn't try to hide his questioning at how the hell she, of all people, survived. The rueful, caught off-guard look on her face as she recognises exactly what he enquired is sobering - it belongs to neither the self-depreciatingly cheerful girl he knew nor the woman with the gallows-humour wit he knows now.

"I was at St. Bart's."

The building both of them called a second home and, more importantly, the secondary location of the outbreak. The morgue, _her_ morgue, the epicentre of the infection vector.

The answer says so much to him in so few words and at the same time does nothing to satisfy his curiosity. Every piece of evidence should point to her being dead, same as he should be.

"It's not every day a corpse gets up from your examining table."

He says nothing, watching, cataloguing her response. Why, he isn't sure. It shouldn't matter, any of it. It won't help. They need to live in the now to live at all. But he indulges the past this one time because it feels oddly like they have no future at that precise moment and what else is there to do?

"She- _it, _it got Greg first. He was leaning over, trying to spot the injection marks I pointed out. Looking a bit green around the gills at having to get so close, same as usual. He was so damn close. I... it happened so fast he couldn't do a thing - I knocked it out with the scales. Thought _she_ was deranged and unexpectedly not dead, a mistake... I didn't want to hurt her."

Sherlock doesn't ask anything more, yet he has opened a floodgate; Molly needs no prompting now – her mutterings slurred as she fills in the details he decides he doesn't want to know after all.

"He was lying there, g-gasping for breath. I rang, for help, and I tr-tried... they got there in a minute – best response time ever, you know, perks of being in a frigging hospital - but there was so much blood...Throat ripped clean across. With teeth."

She places her emptied bottle down unsteadily and takes another eager swig from the jug he hands her, wiping her mouth slowly afterwards with the back of her hand in a motion that belies an attempt to quell nausea too; he doubts it's merely alcohol related.

"He choked on his own blood. I saw it. I saw that second where the light went out of his eyes, face slack. It was horrible. I didn't think it could get any worse. Then I saw him blink and lurch up at one of the student doctors who was calling time of death. And it didn't stop. The screaming, the blood. Every time someone went down you knew they'd get back up, but not as your friend."

Sherlock closes his eyes, giving in to the spinning of the room, not wanting to risk her seeing the empathy they must hold. He hates that he understands what she feels. He doesn't want any of this to be true.

* * *

Logically he knows why it is a hideously bad idea. Physiologically he accepts the need. It drives human psychology. He has, however, mostly been immune or rather, able to control the urge.

His control is obviously breaking. He's clearly formed a strong attachment, the endless days spent together automatically cultivating a life-saving bond of friendship, and he blames that as much as the lack of murder cases.

People die in droves these days, but never in an interesting way, in a way he is sick of and fed up with and he despises the indiscriminate brutality of it. Bad people die and good people die, _people_ die, just because they were in the wrong place, couldn't run fast enough, weren't intelligent enough to escape the throngs stripped of their humanity.

There is no cleverness to be found in the world anymore, except in surviving and it feels evermore the luck of the draw that they keep winning. The prize behind door number two is not finding a zombie.

One day they will lose.

One day they will die; he will die, Molly will die and it's a fact he hates with a vengeance because he knows intelligence isn't everything now. They live now, they die later. He can't predict with accuracy when _later_ is.

Maybe that uncertainty is why he doesn't resist when she wraps her arms around his shoulders; taking the chance to eek out a small pleasure where it can be found. He knows she only means to lay her tired head on his chest, to rest with an illusion of protection in his arms; his leaning down towards her head causes her to look up, shocked. Looking up is what he wants, the lean in timed carefully - slowly so she can notice and react - so that he can capture her lips.

His heart hammers in his chest the same as when he is fighting for his life. Life and death is all the same to him in sensation. It is fear. It is excitement. It is the nervous tremor in his hands. It is _feeling_. Who is he to deem this encounter wrong; why is it damnable to let his body reign for a while when there are lips and teeth waiting for him outside with worse things in mind? Or not in mind, as he reminds himself, another instinct and isn't everyone just heaving over to instinct these days.

He kisses with a ferocity that leaves them both breathless and is every bit as brutal as the scenes in his head, tearing affection away like the pieces of flesh from the images burnt into his memories. Molly has offered him nothing but he takes all that he can, that she lets him. His lips work her exposed salty skin and his hands slide underneath grubby clothes, each action eliciting gasps and moans that leave him exhilarated. Sherlock explores with everything he has – fingers, palms, limbs against limbs – growing harder against her hip, and colder inside his mind, as she becomes softer, warmer, pliant under his control.

It is a bad idea. But he _is_ doing it. He has started it and it needs to stop. Yet he can't simply stop, he reasons; that would be unfair and damaging to their relationship, on which her survival depends. In part, he amends, recognising she crossed London on her own successfully amidst the breakout. They do need each other, though, and in this moment he needs her, a vulnerability he allows fleetingly to be exposed until it just as suddenly passes.

Reality has broken through and he feels foolish and frustratingly aroused.

There is one expedient exit strategy he can think of. He feels he owes her that much, biologically speaking. Something for her to remember this dream-come-true by. It has nothing to do with the noises she makes as he shimmies her knickers down and sucks gently on her clitoris.

* * *

She doesn't ask why it happened.

They don't speak of it at all, in fact. He can, however, sense her hungry stare upon his lips and that unnerves him almost as much as the zombies prowling their vicinity.

* * *

He knows why it happened.

He knows the science of it and the psychology, too. Close quarters, physical proximity, shared stressors.

He's got a taste of her, of the desires he's repressed for years, and he yearns for it again. He dreams with increasing frequency of lapping at the lips of her labia minora, dragging his tongue teasingly upwards to excite the thousands of nerves at her entrance and settling sweetly on her clitoris.

He's unnerved by her examination of him. He has to make it a habit not to feast his eyes on her, to not let her to see the hunger mirrored or the want to return to that shared space and time where they really_ lived_.

* * *

It's the fifth escape from almost certain death they've had in a week when he realises it won't work, this plan of his to detach himself. Their lives are in their bodies and he has to be present in his, he has to _feel_ to retain that edge that keeps him alive and when he feels, he feels _everything_.

He only looks at her for a little longer than he ought to, but she _knows_.

He curses that; she always was good at reading him.

She pounces on the opportunity. Before he knows it, he is pressed to the wall, her battle-roughed hands pulling his head down to hers, and he is rutting against her stomach like the animal he is. He has tried to deny it but, when it comes down to it, when it comes to the end of the world, he can't any longer.

He growls as she crouches down and quickly frees him from his trousers to take him in her mouth. Those lips that he called too small he thanks the existence of as they wrap delicately around the head of his cock. Molly supplements her mouth with her hand to his delight and the next few minutes blur into one blissful sensation of firm, wet, warmth that gathers pace to his ecstasy.

* * *

It's never enough.

A _taste_ of her is not enough. His dreams are torturous imaginings of a touch further. He reaches out to her in moments he doesn't need to. He is obsessed and he is truly scared, because he is distracted. His desire isn't a helpful motivator anymore, it is all-consuming and it will get them killed.

That is why he initiates an encounter outside of the usual parameters. They're reasonably well-situated for once and are about to go to imminent danger instead of having come directly from it.

"I need you," he says in a low voice. He snakes arms around her waist from behind as he stands and presses up to her so she can feel his erection.

"Um, well..." she mumbles, awkwardly turning around in his embrace to gauge his meaning. Any protests die on her lips as he goes straight for licking and nipping her neck just behind her ear, where he knows it will be most effective. He works her neck expertly with his tongue and teeth as his dexterous fingers unbutton her jacket and untie the catches of her handmade holsters, which drop to the floor with clang.

It doesn't take much time to strip Molly of her outer clothing, her hands enthusiastically attempting to help there, in amongst her enjoyment of his attentions, and much as it pains him aesthetically – another reason to hate this forsaken aftermath - he has prepared himself in a conveniently skimpy choice of a thin, not-so-mucky t-shirt and jogging bottoms. At least he doesn't plan to wear them for long.

When they are both clad in underwear alone she pauses, silent, despite his ministrations heading south and he is worried for a moment she means to end it. Molly simply stares at him, like she is searching for something. Whether she finds it or not he isn't sure.

She does move to lie on the floor though, posed alluringly with her legs crossed, drawing his gaze to the mound of hair between them – a behaviour that reminds him of the building ache at the matching area on his own anatomy. He lies on his side next to her and she scoots up to get closer to him, heat radiating from her in contrast to the cold concrete underneath the blanket.

It is Molly who closes the distance he leaves. She seals the deal with a fiery kiss and drapes a leg over his thigh, leaving the tip of his penis temptingly near to her heat. She pulls his body closer with her hands at the base of his spine, pushing him into her slightly. All that remains as a barrier are two scant layers of cloth that mask little of the sensation that awaits were he to move the fabric aside and push in further.

He whispers in her ear and she trembles, presumably at the potent mix of his hot breath and his words.

"Molly Hooper, I do mean to fuck you even if it's the last thing I ever do."

Sherlock leaves out the bit where he reckons it could well be the end of him if this doesn't get her out of his system. He's not aiming for romantic, but he doesn't want to spoil the mood and doubts his thoughts on the matter would be welcomed.

There are no social conventions he could have studied to ensure he does this right. He simply has to see how it goes, where it takes them. He can't think about the future.

Molly appears to be, though.

"What about, er, protection?"

"Minimal risk. Stress and malnutrition make conception unlikely. Besides, you haven't had your menses in over two years, or haven't you noticed?"

Sherlock had, because he had made a point to track her cycles in case it was going to be a problem. The absence of the occurrences handily made room for other supplies, though that hadn't initially been his main concern.

Blood is an attractor of their predators. Inconclusive data to tell if it mattered from that perspective and decidedly moot for them now, he thinks, as he watches Molly wriggle out of her underwear and shucks off his own in response to her unspoken agreement of his proposition.

She is quickly on her side again and pulls him closer with a leg thrown over his hip, fingers sliding his foreskin back and guiding him inside her with a confident determination. She rocks against him, taking him in inch by agonising inch, until there is no space left between them. Sherlock's hips buck of their own accord; he makes a strangled noise foreign to him as he lets go and drowns in the urge to bury himself within Molly.

Moving himself over the top of her, wrapping her legs around his waist, each thrust is preceded by an torturous withdrawal, the denial that causes the enveloping pleasure to intensify.

Sherlock slides in and out of her with a feverish rhythm as she tries herself to grind her sensitive bundle of nerves in time with their meeting his pubic bone. The airy moans she voices at the brief pressure spurn him further, to drive himself home harder and deeper until she has her hands clasping his arse to retain more contact and he can feel her spasming around him.

As thrilling as it is to feel the proof of her climax, he is not quite there himself – on the precipice, eyes closed, waiting for the last step and his fall. His mind flicks to her earlier concern and to the intended purpose of the act. Childrearing would be foolish in this setting and he has no designs to father progeny, but there is an appeal to the notion of the possibility. A purely theoretical desire so primal it unwillingly feeds into his instinct to fuck her, good and hard and proper, and that thought is the push he needs. He comes, pumping his seed into her with a feral grin of satisfaction.

He opens his eyes, wild expression held, as the door in the corner abruptly unlocks and Mycroft strolls in casually to witness them _in flagrante delicto_. There is gunfire and some small amount of terrified shouting off in the distance.

Mycroft's expression never falters, thoughtful and largely passive even in the face of an unexpected twist of limbs and exposed bodies. Perhaps when you've seen literal massacres across the country, the standard embarrassments cease to apply; no issue with spying flesh as long as it isn't chillingly bloodied.

"John is dead."

Sherlock blurts it out like a childish confession to the room, but it is too late. Whatever power there was in the meeting is lost. Mycroft may see the deadness of his eyes under the surprise, but it is no longer about John who died or John who was made the animal, his best friend whose head he put a bullet in and whose gun (useless without ammunition but kept out of idiotic sentiment) has weighed heavily in his pocket every day since.

Mycroft must know as well as he that even those who live have died too.

"Shall we go?" Mycroft asks serenely, leaning on his umbrella – Sherlock hopes he's had the foresight to pack one with a sword. "I have an escort waiting to take us to the facility. I'd have come sooner but it seems you were... occupied."

"Four out of the ten are dead already," Sherlock says, extracting himself from Molly unashamedly. If Mycroft isn't flinching, neither will he. "Wait... make that five."

"Five should be adequate."

"I don't care about the numbers!" came an indignant statement from below, Molly covering herself best she could. "Can you two stop bloody arguing, people are dying. Also, _kindly_ avert your eyes, Mycroft. I need to get dressed or the holsters will chafe like hell, and then whose fault will it be that we die?"

"As you wish," Mycroft acquiesces.

"Hang on," Sherlock says, catching the thread of the conversation Molly unintentionally started, "are you implying I can't take them by myself? You're not the only one with technical prowess in killing."

"How many have you taken out?" she asks sharply as she does up her trousers.

"Oh I don't_ count_," he says, waving his hand to indicate it isn't expressly important to know figures.

Molly straightens her oversized shirt, adjusting her holsters over it and squaring herself up to him.

"I've killed 134 people, Sherlock, and I remember them all. Best I can. Like the people I had on my table. I make it fast when possible because I don't know if they're in there somewhere. I've found eight good methods to do that. You... you hack and slash, you're an amateur."

Sherlock hesitates to give his first thought of reply to the accusation for two reasons. One, he doesn't like the idea of pissing off the woman he just had sex with, tact was clearly needed; and two, he was acutely aware of Mycroft staring at them with a level of scrutiny that indicated a fascination he'd prefer not to encourage if they were going to be bombarded with each other's company for lord knows how many years to come before the whole mess was cleared up.

A quick resolution is required, which is how he ends up uttering the perfectly truthful (but unusually humble) response of, "Thank you for the constructive criticism, Molly. "

"That's fine," she accepts with a nod, "Now why don't we get out of here before the odds tip out of our favour. Mycroft, you might like to stand behind Sherlock maybe? Or use the umbrella. It gets a tad bloody, sorry. You know how it is."

Mycroft gives a look that seems to indicate he distinctly does not know how it is, nor does he wish to, but it's tough luck as his escort is going to prove more of a liability than a help at this rate.

"Or not, I suppose." she finishes weakly.

She secures her backup fire-axe to her pack; walking through the door she calls out behind her with a nervous cheerfulness, "End of the world problems, ha, suppose we're all still getting used to them."

They follow her out into the dingy corridor, Molly stealthily scouting ahead. On the tail-end of their little convoy Sherlock is warming up his muscles with a few practice swipes, which means he witnesses Mycroft opening the umbrella with a sigh. Sherlock laughs a tad hysterically at the absurdity.


End file.
